A Graftable Quaternary Ammonium Biocidal Polymer Reduces Biofilm Formation and Ensures Biocompatibility of Medical Devices

Abstract A quaternized polyvinylpyridine (Q‐PVP) polymer methanolic solution synthesized in a single step is used to covalently graft titanium surfaces. Q‐PVP is quaternized with varying N⁺/N ratios. 1 cm² pure titanium plates are polished and activated. Treated samples are grafted by spin coating or dip‐coating (grafting‐to method). Surfaces are characterized by X‐ray photoelectron spectroscopy, polarization modulation reflection absorption IR spectroscopy, atomic force microscopy, scanning electron microscopy, and surface charge density calculation. Polymer leaching is assessed at 7 days. Biocompatibility is assessed on MC3T3 and L929 cells (MTT‐assay) and SEM. In vitro antibacterial activity is assessed on methicillin‐resistant Staphylococcus aureus (MRSA) at 1 and 24 h (37 °C in brain heart infusion) and at 7 days in a biofilm model. Polymers exceeding 31.3 ± 0.7% quaternization led to bactericidal surfaces. Bactericidal activity increased with surface cationic density. Surface cationic density and biocompatibility are inversely correlated. Polymers with 44.6 ± 1.2% quaternization are antibacterial and biocompatible. High‐density Q‐PVP inhibited MRSA biofilm formation. Q‐PVP is a promising candidate for antibacterial surface modification. Further in vivo studies are required.